When you purchase your next
gemstone be sure to ask if the gemstone has had any treatments, as this can
affect the value and durability of the gemstone. A good jeweller will
automatically make this disclosure as part of the sale.

If you are purchasing a
high-value gemstone such as Ruby, Emerald or Sapphire make sure it has a
certificate from a laboratory that has the expensive equipment required to be
able to detect some of these treatment. Most jewellers and gemologists have
equipment that can detect certain levels of treatment, but it is only the
laboratory equipped grading companies such as Gemological Institute of America
and European Gemological Laboratory that can detect all the treatments
available.

There are 10 major gem treatments
that require disclosure from the seller to the buyer.

Cavity
Filling. This type of treatment refers to those gemstones that have
defects on the surface of the gemstone; these cavities and surface reaching
fractures reduce the appearance and value of the gemstone. To enhance the value
these imperfections are filled with different resins, plastic or glass, which
improves the appearance and increases the gemstone weight. Due to the different
Reflective Index of the filler material most gemologist can detect the fillers.

Dying.
Is used to enhance the color of gemstones such as Chalcedony, Lapis, Jadeite,
Cultured Pearl and Turquoise. These gemstones have one thing in common they are
all porous, which enables the dye to reach just below the surface. To assist in
having the dye penetrate, some gemstones are heated and then cooled quickly by
quenching in water, this causes minute surface cracks into which the dye will
flow. The more color a gemstone has the more appealing to the consumers.

Heat
Treatment.
This is the most common among treatments and is used
extensively on corundum (Sapphire, Ruby) to enhance the color of the gemstone.
Heat can also be used to remove internal blemishes, or color centres to improve
the gemstones color consistency. Most gemstones that are heated result in
enhancing or changing the color are stable, however they are still enhancement
and should be disclosed.

Irradiation.
You will find this treatment in some colored gemstones and colored
Diamonds. This process began in the early 1990s and is used widely today, there
are minimal traces of radiation in the gemstone but its never harmful if the
correct procedures have been followed. The challenge in gemstones is the lack of
stability and its sensitivity to heat once the process has been completed.
Therefore it is important that you know the gemstone has been irradiated, if you
ever have a jewellery item repaired make sure the stone is removed, as the heat
will change the color. Most colored Diamonds are made affordable by irradiating
the natural browns and yellow, which can turn them into blue, green and red
colors making them more attractive and increasing their value. The process in
diamonds is more stable but is still susceptible to changes with heat.

Surface
Diffusion.
This treatment is becoming more common today with the
enhancement of more valuable gemstones such as corundum. The gemstone is heated
just below melting point, and then chemicals are used to penetrate the surface
to become part of the crystal structure. This process is also used to produce
stars (asterism) in some gemstones, again increasing value.

Disclosure.
It is not only
unethical, it is also against the law to sell a natural gemstone that has been
treated and not disclose the treatment. If a jeweller or gemologist does not
know if a gemstone has had a treatment then he should assume it has and disclose
it, or send to a laboratory to confirm one way or another. All treatments must
be disclosed at the time of sale to the consumer. Unfortunately, today there are
a lot of treated gemstones being sold as natural.

The reason sellers fail to
disclose falls into four main categories:

Ignorance,
they believe their suppliers, who mostly live in countries where these rules are
not adhered to or do not exist.

Competitive
Pressure, they feel they will be disadvantaged in a sale if their
competitors do not disclose.

Resistance,
they do not believe in the rules and do what they think is right.

Calculated
Risk, If they don’t disclose how often will they get caught and if they
are caught they can probably make the problem go away by refunding or replacing
the item.

A reputable seller will always
offer disclosure, but its not a perfect world.

Derek Parnell is a Graduate
Gemologist (GIA) and owner of
Jewels by Truros a
division of Truros Corporation. Truros Corporation has
interests in the Jewelry and the Real Estate Industry.
For more information you can reach Derek atJewels by Truros.